Kihwal Lee created HDFS-11817:
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Summary: A faulty node can cause a lease leak and NPE on accessing
data
Key: HDFS-11817
URL: https://issues.apache.org/jira/browse/HDFS-11817
Project: Hadoop HDFS
Issue Type: Bug
Affects Versions: 2.8.0
Reporter: Kihwal Lee
Priority: Critical
When the namenode performs a lease recovery for a failed write, the
{{commitBlockSynchronization()}} will fail, if none of the new target has sent
a received-IBR. At this point, the data is inaccessible, as the namenode will
throw a {{NullPointerException}} upon {{getBlockLocations()}}.
The lease recovery will be retried in about an hour by the namenode. If the
nodes are faulty (usually when there is only one new target), they may not
block report until this point. If this happens, lease recovery throws an
{{AlreadyBeingCreatedException}}, which causes LeaseManager to simply remove
the lease without finalizing the inode.
This results in an inconsistent lease state. The inode stays
under-construction, but no more lease recovery is attempted. A manual lease
recovery is also not allowed.
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